Fluid couplings utilizing self-sealing valves within the coupling halves or parts permit two fluid circuits to be connected and disconnected while one or both of the circuits are pressurized without significant loss of fluid. The self-sealing valves usually engage during the final stage of connection of the coupling parts and displace each other to an open condition establishing communication between the respective fluid circuits. During disconnection separation of the self-sealing valves permits automatic closure to seal the passage of each part.
When connecting self-sealing coupling parts, the forces imposed on the self-sealing valves by the associated pressurized fluid must be overcome, and the "piston" effect of a self-sealing valve exposed to pressurized fluid may render it difficult to fully couple the parts. Coupling is particularly difficult to achieve if both of the coupling parts are pressurized wherein fluid pressure is acting upon both of the self-sealing valves and must be overcome when connecting the parts to completion.
Fluid couplings used with agricultural equipment, such as those mounted upon tractors, are used to supply pressurized hydraulic fluid to implements hitched to the tractor, and such couplings must be readily connected and disconnected, self-sealing, and of the "breakaway" type wherein the coupling parts may automatically separate when the axial tension in the hose lines of the implement reaches a predetermined force. In agricultural equipment couplings it is not uncommon for pressurized fluid to exist within each coupling part, one of the parts pressurized by the tractor hydraulic system, the other part being pressurized due to the weight of the implement hydraulically operated components, and commonly, agricultural couplings often use manual actuators to assist in the coupling operation.
Fluid self-sealing couplings using manual actuators are known, and typical coupling constructions are shown in U.S. Pat. Nos. 3,710,823; 4,009,729 and 4,222,411. Also, it is known to incorporate power-assisted features into self-sealing fluid couplings to aid connection of the coupling parts while under pressure, and examples of such devices are shown in U.S. Pat. Nos. 3,646,964; 4,303,098 and in the assignee's U.S. Pat. No. 4,540,021.
While some of the problems of interconnecting self-sealing fluid couplings under pressure are met by the prior art devices disclosed in the aforementioned patents, the cost of producing such couplings is high, and such prior art devices do not overcome all of the problems existing with this type of coupling.
It is an object of the invention to provide a self-sealing fluid coupling utilizing a manually operated actuator wherein the coupling incorporates structure permitting pressurized fluid to be utilized in achieving the coupling connection.
It is another object of the invention to provide a self-sealing coupling employing a manual actuator to initiate connection and disconnection of the coupling parts wherein only small forces need be imposed upon the manual actuator to achieve the coupling operation even though one or both of the coupling parts may be under pressure.
Yet another object of the invention is to provide a self-sealing power-assisted fluid coupling having a manual actuator wherein coupling of the parts is achieved by forces resulting from the supply of pressurized fluid and disconnection of the coupling parts is readily achieved.
A further object of the invention is to provide a self-sealing coupling employing a manual actuator wherein the actuator operates a valve component controlling pressurized fluid pressure to permit a power-operated connection of the coupling parts, the power-assisted connection being accomplished through an expansible chamber motor concisely defined in one of the coupling parts, and a second expansible chamber motor being utilized to neutralize the effect of the first motor to permit manual operation of the actuator in the disconnection operation with little exertion.
Yet a further object of the invention is to provide a self-sealing fluid coupling of the power-assisted type wherein the coupling parts will automatically disconnect upon excessive tension forces being applied thereto to prevent damage to the associated conduits and hose line.
In the practice of the invention the coupling female part includes a passage connected to the pressurized fluid supply and the outer end of the passage is closed by a spring biased self-sealing valve arrangement. An annular sleeve is mounted upon the female part for axial displacement thereon between extended and retracted positions, and the sleeve includes an open outer end which extends beyond the female part self-sealing coupling for receiving the nose of the male part. Radially displaceable detents in the form of balls are mounted upon the outer end of the sleeve for cooperation with a groove formed in the male part nose, and the female part includes a detent operating actuator which locks the male part to the sleeve as the sleeve is retracted into the female part.
The portion of the female part circumscribed by the sleeve includes a radial shoulder which defines opposed radial surfaces on opposite sides thereof, and the shoulder includes a seal engaging an inner cylindrical sleeve surface. The sleeve includes radial annular surfaces in opposed relationship to the female part shoulder surfaces, and as the sleeve is axially displaced on the female part first and second annular expansible motor chambers are defined by the radial sleeve and shoulder surfaces upon opposite axial sides of the shoulder.
The sleeve includes an outer cylindrical diameter, and an annular axially displaceable control valve encompasses the sleeve cylindrical diameter and includes a pair of axially spaced seals engaging the sleeve. A radial clearance exists between the sleeve outer diameter and the valve inner diameter and this clearance forms a portion of a fluid circuit interconnecting the first and second expansible motor chambers defined by the female part shoulder and sleeve radial surfaces.
A passage in the female part establishes communication between the side of the female part shoulder remote from the sleeve open end, and a second passage defined in the sleeve establishes communication between the first sleeve chamber and the control valve clearance. A third passage interconnects the clearance between the sleeve and control valve with the sleeve chamber disposed on the side of the female part shoulder toward the sleeve outer end. The effective areas of the pressure faces defined on the sleeve in the first and second expansible motor chambers for producing axial forces on the sleeve are substantially equal.
A manual actuator is rotatably mounted upon the female part by means of a hand-operated lever, and the actuator includes a hub having an eccentrically located pin received within an annular groove defined on the control valve. Thus, rotation of the actuator produces an axial displacement of the valve on the sleeve.
In the disconnected state the actuator will be rotated to a position which shifts the valve toward the female part open end and the valve includes an end which abuts a snap ring on the sleeve which axially displaces the sleeve its maximum extent toward the open end of the female part. In this position, the detent actuator releases the detents and permits the nose of the male coupling part to be inserted into the sleeve open end for a sealed relationship thereto.
Upon the male part being fully inserted into the sleeve open end the manual actuator is rotated to displace the valve in an axial direction away from the female part open end, and this valve movement positions the valve seals on the sleeve such to close the second chamber with respect to the pressurized fluid within the female part and permit exhausting of the second chamber. Simultaneously, the first sleeve chamber will continue to be exposed to the pressurized fluid within the female part, and the first chamber produces an axial force on the sleeve which retracts the sleeve into the female part drawing the male part therein, and the detent acutator causes the detents to grip the male part locking the male part to the sleeve. As the male part is drawn into the female part by the pressure within the sleeve first chamber, the engagement of the parts' self-sealing valves may open one, or both, of the self-sealing valves prior to the parts being fully coupled, but as the area of the end of the male part exposed to pressurized fluid is of a lesser area than the pressure face area of the first chamber, retraction of the sleeve and male part will continue until the coupling parts are fully connected.
When disconnecting the coupling parts the manual actuator is rotated to a position which shifts the valve on the sleeve establishing communication between the pressurized fluid within the female part and the shoulder and sleeve surfaces defining the pressure faces of the second sleeve chamber. This movement of the control valve terminates the exhausting of the second chamber and pressurizes the second chamber, and as equal pressure now exists within the first and second sleeve chambers, the substantially equal faces of these chambers will counterbalance or neutralize the biasing force imposed on the sleeve by the fluid within the first chamber and continued rotation of the manual actuator displaces the valve for engagement with the sleeve shifting the sleeve toward the female part open end and at the extreme extension of the sleeve the detent actuator releases the detents permitting the male part to be removed from the sleeve. Very little force is required to be exerted on the manual actuator during disconnection of the coupling parts, and during the initial stages of disconnect, fluid force acting upon the male part end aids in the extension of the sleeve.
If, while the parts are coupled, high tension forces are imposed upon the male and female parts, upon such tension overcoming the biasing force imposed on the sleeve by the first chamber the sleeve is displaced toward the female part open end to the fully disconnect position which permits the detent actuator to release the detents freeing the male part from the sleeve.